Treated stone.



ROY W. HYDE, OF LAKEWOOD, OHIO.

TREATED STONE.

No Drawing.

To all whom it may concern:

Be it known that I, RorW. HYDE, a citizen of the United States, residing at Lakewood, in the county of Ouyahoga and State of Ohio, have invented certain new and useful Improvements in Treated Stones, of which the following is a specification.

This invention has reference to a natural stone treated with a vegetable oil, and the object of the invention is, more particularly, to prepare natural stone for use in switchboards, panel boards, switch bases and the like for electric light and power installations and as a substitute for slate and marble as heretofore exclusively used for these purposes. To these ends, I employ a natural stone of a suitable grade and formation, say a certain rather fine grained blue standstone found in quarries in Ohio and elsewhere, and impregnate the same with a suitable oil, say, linseed oil, by immersion or a vacuum or other process which will completely saturate the stone with the oil, all as hereinafter fully described and particularly pointed out in the claims.

Heretofore switchboards and parts associated therewith in the service above indicated have been limited to either slate or marble as above stated, and therehas been no practical substitute or alternate for these purposes, so far as I know or believe. But there are well known objections and limitations to both slate and marble which remove them quite a way from the ideal conception or article for these uses, and yet both have been exclusively used heretofore because nothing better was available. Take slate for example in switchboards for illuminating and power equipment. These boards have at last been standardized and cover a large range of requirements. Standard panels are advisable for general use although special conditions may usually be met with small modifications of the standards. The material from which panels should be made varies with the service, but, plain slate can be used where the potentials do not exceed 750 volts. Above this pressure the plain slates are impossible and higher and better grades are demanded. Yet at its best, slate of any kind will not withstand more that 1100 volts, and above that figure it is necessary to employ a suitable grade of marble. Then again even the best varieties of slate are liable to contain metallic and other impure veins or leads which render them use- Specification of Letters Patent.

Patented Aug. 29, 1916.

- Application filed December 18, 1914. Serial No. 877,998.

less for electrical purposes, and they also are liable to be more or less filled with hard or fiinty spots which make drilling for the usual mountings diflicult or practically impossible on uniform lines. Altogether therefore, the supply of slate with all the requisite qualities and without the fatal obj ections is exceedingly limited and the prices are correspondingly high.

Marble is largely used for switchboard panels, especially in high tension work, because of its excellent insulating and workable qualities, but, like slate, it is very liable to have metallic or other impure traces or seams which a high pressure will follow and thus render the board unserviceable. However, there are several varieties of marble available for these uses which give general satisfaction, such as the white Italian, pink or gray Tennessee, and several varieties of blue Vermont. Apart from the possible short circuiting in or through the metallic veins in the best known marbles, the high price of an all marble installation is probably its most serious objection from a financial point of view.

Now, I have discovered and made a substitute for both slate and marble which possesses all the best qualities of both and none of the serious or vital objections, and at an initial cost which is materially less than slate and far less than marble. This substitute or article consists of natural stone, and preferably a rather refined grade of socalled blue sand stone as above indicated, and which is treated and prepared by thoroughly impregnating the same with linseed oil. Linseed oil is especially well adapted to my purpose, and possibly exclusively, because it will flow freely when suitably heated in the process of impregnation and cannot be driven out or burned out under the highest electrical temperatures. In other Words the saturation or impregnation, once made, is found to be fixed and permanent and practically the same as if it were a homogeneous portion of the natural stone itself. Of course all stones should be first thoroughly dried out in a furnace at a suitably high heat, say 300 degrees Fahrenheit, before being placed in the solution. Then if impregnation is to be by bath, the oil will be heated and kept at a temperature, say of about, 180 degrees Fahrenheit during the entire period of immersion, say thirty to eighty hours, according to the kind or quality and thickness of the stone and other conditions. If impregnation be by vacuum or artificial pressure a much shorter time will sufiice, the oil being heated as before and the stone immersed therein.

The blue sand stone above referred to and preferably employed at this time is known to have a very fine grain and is exceedingly strong in its natural state, being able to withstand a breakage test of 8000 volts. After treatment by my process a breakdown test of 82,000 volts has been withstood without any sign of impairment or injury. This stone also has been foundto be free from minerals and other deleterious substances.

The. method of manufacture herein described is divided out of this application and made the subject matter of another application to be filed thereon.

The process herein described is divided ROY W. HYDE.

Witnesses:

H. T. FISHER, F. J. Gnnnn.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

